TW202216423A - Fiber reinforced plastic, integrally molded product, and prepreg - Google Patents

Abstract

The present invention relates to a fiber reinforced plastic including a reinforcing fiber group including reinforcing fibers, a thermosetting resin layer including a first thermosetting resin, and a thermoplastic resin layer, wherein the thermoplastic resin layer is included as a surface layer of the fiber reinforced plastic, an interface between the thermoplastic resin layer and the thermosetting resin layer is located inside the reinforcing fiber group, and the thermoplastic resin layer includes a disperse phase of a second thermosetting resin.

Description

Fiber-reinforced plastics, integral moldings, and prepregs

The present invention relates to fiber-reinforced plastics, integrally formed products, and prepregs.

Fiber-reinforced plastics that use thermosetting resins as matrix resins and are combined with reinforcing fibers such as carbon fibers or glass fibers are lightweight, but have excellent mechanical properties such as strength and rigidity, heat resistance, and corrosion resistance. Therefore, it is used in aviation. Space, automobiles, railway vehicles, ships, civil construction and sporting goods and many other fields.

However, fiber-reinforced plastics are not suitable for manufacturing parts or molded bodies with complex shapes in a single forming step. In the above-mentioned applications, components containing fiber-reinforced plastics must be fabricated and then made by joining, fastening, etc. to other components. integration.

For example, as a method of integrating fiber-reinforced plastics with members of the same type or different types, mechanical joining methods using bolts, rivets, screws, etc., or joining methods using an adhesive are employed. In the mechanical joining method, there is a problem in that the strength around the hole portion decreases because holes are formed in fiber-reinforced plastics and other members. In the case of passing through the adhesive, bonding occurs due to peeling at the interface between the fiber-reinforced plastic molded body and other members. Then the bad subject. In addition, such bonding requires a step of processing the bonding portion in advance, such as a hole drilling step and an adhesive application step, and there is a problem in that the manufacturability is lowered.

Therefore, a fiber reinforced plastic having a thermoplastic resin on its surface has been proposed as a method of bonding with other members without making holes in the fiber-reinforced plastic and tightening it, or as a method of bonding with other members without passing through an adhesive.

Patent Document 1 discloses a layered product in which a thermoplastic resin layer disposed on the surface and a thermosetting resin layer serving as a matrix resin of fiber-reinforced plastic are integrated to have a concavo-convex shape, and a method for producing the same. By integrating the thermoplastic resin layer and the thermosetting resin layer having a concavo-convex shape, these strong joints can be achieved. Furthermore, by arranging the thermoplastic resin layer on the surface, the thermoplastic resin layer can be melted, and the other adherends and the fiber-reinforced plastic can be joined.

Patent Document 2 discloses a laminated molded product obtained by impregnating a thermosetting resin material in which fine gaps are formed, and a method for producing the same. Since the thermoplastic resin material is inserted between the fiber-reinforced layer and the fiber-reinforced layer, the interlayer toughness of the molded product is improved. Patent Document 3 discloses a resin molded body obtained by joining a thermoplastic resin molded body and a thermosetting resin molded body having a thermoplastic resin portion provided to be exposed on a part of the surface by welding. Since it has a thermoplastic resin part and can be integrated by welding, the thermoplastic resin molded body and the thermosetting resin molded body can be joined without using an adhesive or a fastening member such as a rivet. Patent Document 4 discloses a joined body formed by integrating a first formed body and a second formed body with reinforcing fibers exposed, and a method for producing the joined body. Since the second molded body is entangled with the exposed portion of the reinforcing fibers formed on the surface of the first molded body, the bonding strength is improved. [Prior Art Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2004/060658 [Patent Document 2] International Publication No. 2008/020628 [Patent Document 3] Japanese Patent Laid-Open No. 2016-175397 [Patent Document 4] Japanese Patent Laid-Open No. 2017-39234

[The problem to be solved by the invention]

The layered product described in Patent Document 1 can effectively utilize properties such as strength and rigidity of the fiber-reinforced resin without the need for openings or adhesives, and the bonding procedure is simple, so it has a high degree of processability. However, in order to expand the application range as a product, it is necessary to further improve the bonding quality. For example, since the thermoplastic resin layer flows during welding, there may be concerns such as thickness fluctuations and disordered orientation of reinforcing fibers. The laminated molding product described in Patent Document 2 has a structure that focuses on interlayer properties, and when the thermoplastic resin material is disposed on the surface, the thermoplastic resin material can be regarded as an adhesive layer at the time of welding. However, in the laminated molded product, since the thermoplastic resin material is impregnated with the thermosetting resin and is in a buried state, it is difficult to sufficiently secure the bonding area at the time of welding. That is, it is not suitable for the process of joining with another to-be-adhered material which is a subject.

The joined body described in Patent Document 3 is constructed by embedding a thermoplastic resin member that becomes an adhesive layer during welding only in a thermosetting resin member. Therefore, the thermoplastic resin member easily flows out during welding, making it difficult to control the thickness of the adhesive layer. Furthermore, it does not disclose that there is a reinforcing structure at the interface between the thermosetting resin member and the thermoplastic resin member, and the bonding strength thereof may be insufficient.

The bonding system described in Patent Document 4 applies sand grinding or flame treatment to the surface of SMC (Sheet Molding Compound) with thermosetting resin as matrix resin to expose fibers, and then CFRP with thermoplastic resin as matrix resin is fused to the surface, Attempts are made to achieve high-strength bonding by forming reinforcing structures. However, methods such as sanding or flame treatment, which greatly damage the molded body, cannot satisfy the quality, and the exposed fibers are also damaged. Therefore, the effect of fiber reinforcement is limited.

Then, the subject of the present invention is to provide a fiber-reinforced plastic and an integrally molded product which can suppress the outflow of resin and the orientation disorder of fibers during integration, thereby exhibiting excellent bonding strength, and a fiber-reinforced plastic capable of forming the fiber-reinforced plastic and having a high-level process. Sexual prepreg. [means to solve the problem]

As a result of detailed and repeated studies, the inventors of the present invention have found that the above-mentioned problems can be solved, and have completed the present invention. That is, the present invention is as follows. [1] A fiber-reinforced plastic comprising: a reinforcing fiber group containing reinforcing fibers, a thermosetting resin layer containing a first thermosetting resin, and a thermoplastic resin layer, wherein the thermoplastic resin layer is used as a surface layer of the fiber-reinforced plastic, and the The interface between the thermoplastic resin layer and the thermosetting resin layer is located inside the reinforcing fiber group, and the thermoplastic resin layer includes a dispersed phase of the second thermosetting resin. [2] The fiber-reinforced plastic according to [1], wherein the reinforcing fibers contained in the thermoplastic resin layer are in contact with the dispersed phase of the second thermosetting resin. [3] The fiber-reinforced plastic according to [1] or [2], wherein the reinforcing fibers contained in the plurality of the thermoplastic resin layers are bonded by the second thermosetting resin. [4] The fiber-reinforced plastic according to any one of [1] to [3], wherein the major axis length of the dispersed phase of the second thermosetting resin is 50 nm or more. [5] The fiber-reinforced plastic according to [4], wherein the major axis length of the dispersed phase of the second thermosetting resin is 1 μm or more. [6] The fiber-reinforced plastic according to any one of [1] to [5], wherein the volume ratio of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer in the cross section in the thickness direction is relative to the reinforced plastic The said thermoplastic resin layer in a fiber group is 10 volume% or more with respect to 100 volume%. [7] The fiber-reinforced plastic according to any one of [1] to [5], wherein in a cross section in the thickness direction, the volume ratio of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer is relative to the The amount of the reinforcing fibers contained in the thermoplastic resin layer is 3% by volume or more and 50% by volume or less with respect to 100% by volume. [8] The fiber-reinforced plastic according to any one of [1] to [5], wherein the sum of the volume ratios of the reinforcing fibers and the second thermosetting resin contained in the thermoplastic resin layer is relative to the cross section in the thickness direction. Among them, it is 10 volume % or more of 100 volume % of the area|region from the interface of the said thermoplastic resin layer and the said thermosetting resin layer toward the said thermoplastic resin layer surface 50 micrometers. [9] The fiber-reinforced plastic according to any one of [1] to [8], wherein the second thermosetting resin and the first thermosetting resin are the same kind of resin. [10] The fiber-reinforced plastic according to any one of [1] to [9], wherein the glass transition temperature of the second thermosetting resin is 150° C. or higher. [11] An integrally formed product, wherein a first member and a second member are joined through the thermoplastic resin layer of the fiber-reinforced plastic, and the first member comprises the fiber-reinforced plastic according to any one of [1] to [10] . [12] The integrally molded product according to [11], wherein in the integrally molded product, the distance t between the thermosetting resin layer and the second member is 10 μm or more. [13] A dispersed phase prepreg comprising: a reinforcing fiber group containing reinforcing fibers, a thermosetting resin layer containing a first thermosetting resin, and a thermoplastic resin layer, wherein the thermoplastic resin layer is provided as a surface layer of the prepreg , the interface between the thermoplastic resin layer and the thermosetting resin layer is located inside the reinforcing fiber group, and the thermoplastic resin layer includes a second thermosetting resin in contact with the reinforcing fiber. [14] The prepreg according to [13], wherein the major axis length of the dispersed phase of the second thermosetting resin is 1 μm or more. [15] The prepreg according to [13] or [14], wherein the sum of the volume ratios of the reinforcing fibers and the second thermosetting resin contained in the thermoplastic resin layer is relative to the amount of the thermoplastic resin in the cross section in the thickness direction. The interface between the resin layer and the thermosetting resin layer is 10 vol % or more for 100 vol % of the region of 50 μm on the surface of the thermoplastic resin layer. [16] The prepreg according to any one of [13] to [15], wherein the second thermosetting resin and the first thermosetting resin are the same kind of resin. [17] The fiber-reinforced plastic according to any one of [1] to [10], the one-piece molded product according to any one of [11] or [12], or the prepreg according to any one of [13] to [16] As the aforementioned reinforcing fibers, reinforcing fibers having a surface free energy of 10 to 50 mJ/m ² as measured by the Wilhelmy method are used. [Effect of invention]

According to the present invention, it is possible to obtain a fiber-reinforced plastic and integral molding which can suppress the outflow of resin and the disorder of orientation of fibers in a high temperature state for fusion and integration with the second member, thereby exhibiting excellent bonding strength and quality. product, and a prepreg capable of forming the fiber-reinforced plastic and having high processability.

[Form for carrying out the invention]

The present invention will be described below with reference to the drawings as appropriate, but the drawings are for facilitating understanding of the present invention and do not limit the present invention at all. ＜Prepreg＞ The prepreg of the present invention includes: a reinforcing fiber group containing reinforcing fibers, a thermosetting resin layer containing a first thermosetting resin, and a thermoplastic resin layer, wherein, having the aforementioned thermoplastic resin layer as a surface layer of at least one side of the aforementioned prepreg, The interface between the thermoplastic resin layer and the thermosetting resin layer is located inside the reinforcing fiber group, The thermoplastic resin layer includes a dispersed phase of the second thermosetting resin in contact with the reinforcing fibers (hereinafter, it may be simply referred to as a dispersed phase).

FIG. 1 is a schematic diagram of a cross section perpendicular to the plane of a prepreg of an embodiment of the present invention. The prepreg according to the embodiment of the present invention, as shown in FIG. 1 , includes: a reinforcing fiber group 12 containing reinforcing fibers 1 and 14 , a thermosetting resin layer 2 containing a first thermosetting resin, and a thermoplastic resin layer 3 . The surface layer of the impregnated product is the thermoplastic resin layer 3 , the interface between the thermoplastic resin layer 3 and the thermosetting resin layer 2 is located inside the reinforcing fiber group 12 , and the thermoplastic resin layer 3 includes the second thermosetting resin dispersed phase 4 in contact with the reinforcing fibers 14 . In the embodiment shown in FIG. 1 , the thermoplastic resin layer 3 constitutes the entire surface of the prepreg surface layer, but as described later, the thermoplastic resin layer 3 may constitute only a part of the prepreg surface layer.

In the prepreg of the embodiment of the present invention, the dispersed phase 4 of the second thermosetting resin refers to the thermoplastic resin layer observed in the cross section perpendicular to the plane of the prepreg. The region as the principal component. For example, the dispersed phase 4 of the second thermosetting resin in contact with the reinforcing fibers 14 is partially independent as a discontinuous region in the continuous region mainly composed of the thermoplastic resin. In addition, taking the sea-island structure as an example, the thermoplastic resin layer is the sea phase, and the dispersed phase of the second thermosetting resin in contact with the reinforcing fibers corresponds to the island phase. That is, the thermoplastic resin layer 3 can be said to have a sea-island structure in which an island phase containing a thermosetting resin as a main component is dispersed in a sea phase containing a thermoplastic resin as a main component.

Further, in the thermoplastic resin layer 3 including the dispersed phase 4 and the reinforcing fibers 14 , it is preferable that the second thermosetting resin is in contact with the plurality of reinforcing fibers 14 to form the dispersed phase 4 of the second thermosetting resin. That is, in the prepreg of the present embodiment, the plurality of reinforcing fibers contained in the thermoplastic resin layer are brought into contact with the dispersed phase of the second thermosetting resin, so that the plurality of reinforcing fibers can be regarded as partially bonded to each other, and the forming process is completed. Even when the thermoplastic resin layer is in a fluid state due to high temperature conditions, the orientation disorder and movement of the reinforcing fibers can be suppressed, and the thermoplastic resin layer can be prevented from flowing out excessively, and the thermoplastic resin layer serving as the adhesive layer can be secured. thickness, etc., and can contribute to the improvement of quality.

The shape of the dispersed phase of the second thermosetting resin is not particularly limited as long as it is an independent region. For example, in the cross section perpendicular to the plane of the prepreg, when the cross section of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer is observed, it can be fibrous, circular, oval, rectangular, or a complex shape with unevenness. . Here, the long axis length of the dispersed phase of the second thermosetting resin is preferably 50 nm or more, more preferably 100 nm or more, still more preferably 300 nm or more, and still more preferably 1 μm or more. By setting the major axis length of the dispersed phase of the second thermosetting resin within this range, the flow of the thermoplastic resin layer can be effectively suppressed under high temperature conditions during molding and welding, thereby ensuring higher quality. The long-axis length of the dispersed phase of the second thermosetting resin can be confirmed by a conventional method of observing a cross-section perpendicular to the fiber direction of the prepreg. Examples include: a method of measuring from a cross-sectional image obtained by using X-ray CT, a method of measuring from an elemental analysis distribution image obtained by an energy dispersive X-ray spectrometer (EDS), a method of measuring from an optical microscope, a scanning electron microscope (SEM) or transmission electron microscope (TEM) to observe the cross-section image obtained by the measurement method. In addition, the long axis of the disperse phase of the second thermosetting resin is the farthest distance through the outer circumference of the disperse phase of the second thermosetting resin among the straight lines inside the disperse phase of the second thermosetting resin confirmed in the above-mentioned cross-sectional observation image The 2-point line segment, for at least 20 randomly selected dispersed phases, is expressed as the average of the measured lengths.

In the prepreg of the embodiment of the present invention, the volume ratio of the dispersed phase of the thermosetting resin contained in the thermoplastic resin layer in the cross section in the thickness direction is as long as 100% by volume of the thermoplastic resin layer in the reinforcing fiber group. 1 vol % or more may be sufficient, but from the viewpoint of more effectively suppressing the flow of the thermoplastic resin layer under high temperature conditions during molding and welding, it is preferably 10 vol % or more, and further preferably 15 vol % or more. The said volume ratio (volume %) can use the conventional method of observing the cross section orthogonal to the fiber direction of a prepreg. For example, a method of measuring from a cross-sectional image obtained by X-ray CT, a method of measuring from an elemental analysis distribution image obtained by an energy dispersive X-ray spectrometer (EDS), or a method of measuring from an optical microscope or a scanning electron microscope ( SEM) or transmission electron microscope (TEM) to observe the cross-section image obtained by the measurement method.

From the viewpoint of performing welding with the second member with higher quality, the dispersed phase of the second thermosetting resin is preferably distributed in the thermosetting resin layer and the thermoplastic resin layer rather than uniformly dispersed in the thermoplastic resin layer The thermoplastic resin layer near the interface.

Specifically, in the cross section in the thickness direction of the prepreg, when the area of 50 μm from the interface between the thermoplastic resin layer and the thermosetting resin layer toward the surface of the thermoplastic resin layer is taken as 100% by volume, the reinforcement contained in the thermoplastic resin layer is 100% by volume. The sum of the volume ratios of the fibers and the second thermosetting resin is preferably 10% by volume or more, more preferably 10% by volume or more and 90% by volume or less, and still more preferably 20% by volume or more and 70% by volume or less. By making it into a more preferable range, flow of a thermoplastic resin layer can be suppressed more effectively under the high temperature conditions at the time of shaping|molding and welding.

(Interface between thermosetting resin layer and thermoplastic resin layer) In the prepreg of the embodiment of the present invention, the interface between the thermosetting resin layer and the thermoplastic resin layer is located inside the reinforcing fiber group.

The shape of the interface is preferably a concavo-convex shape from the viewpoint of further enhancing the mechanical bonding force. The means for confirming the uneven shape of the interface is not particularly limited, but can be confirmed by observing a cross section perpendicular to the fiber direction of the prepreg. In addition, the most preferable interface shape is described below. The cross-sectional observation surface of the prepreg will be described with reference to FIG. 2 .

For example, as shown in FIG. 2, the cross-sectional observation surface 8 is the difference 90 between the clockwise and counterclockwise rotation of the thermosetting resin layer in the prepreg 5 and the fiber direction 6 of the reinforcing fiber group 12 contained in the thermoplastic resin layer. The direction of the angle is a cross section obtained by cutting the plane perpendicular to the prepreg (thickness direction of the prepreg).

Here, as a method of measuring the profile curve, a known method can be used. Examples include: a method of measuring from a cross-sectional image obtained by X-ray CT after curing the prepreg; a method of measuring from an elemental analysis distribution image obtained by an energy dispersive X-ray spectrometer (EDS); or A method of measuring from a cross-section observation image obtained by an optical microscope, a scanning electron microscope (SEM) or a transmission electron microscope (TEM). During the observation, in order to adjust the contrast, the thermosetting resin layer and/or the thermoplastic resin layer may also be dyed. An example of the measurement method of the profile curve is shown using FIG. 3 .

In the observation image 9 shown in FIG. 3 , the thermosetting resin layer 2 and the thermoplastic resin layer 3 are in close contact with each other, and are displayed as an interface 10 in the observation image 9 . Moreover, the interface 10 is in contact with the plurality of reinforcing fibers. Using the surface 100 on the thermoplastic resin layer 3 side of the observation image 9 as a reference line, vertical lines 120 are drawn at intervals of 10 μm from the thermoplastic resin layer 3 toward the thermosetting resin layer 2 . The point at which the vertical line drawn from the reference line intersects the thermosetting resin layer 2 for the first time is marked, and the line formed by connecting the marked points is used as the profile curve 130 . It can be confirmed that the cross-sectional curve 130 has a concave-convex shape with respect to the reference line.

The average thickness of the entire prepreg is not particularly limited, but from the viewpoint of productivity, it is preferably 50 μm or more and 400 μm or less, and when the average thickness of the entire prepreg is 100%, the thickness of the prepreg is not limited. From the viewpoint of drape property and handleability, the average thickness ratio of the thermoplastic resin layer is preferably 2% or more and 60% or less, more preferably 5% or more and 30% or less. As an example of a method for measuring the average thickness of the entire prepreg and the average thickness of the thermoplastic resin layer, the following method can be mentioned: observing a cross section of the prepreg with an optical microscope Among them, 10 measurement positions are defined at equal intervals, and the average value of the measurement data at a total of 100 positions is used as the average thickness of the entire prepreg and the average thickness of the thermoplastic resin layer.

In the prepreg according to the embodiment of the present invention, the impregnation rate of the thermosetting resin and thermoplastic resin (hereinafter simply referred to as resin) to the reinforcing fiber group is preferably 80% or more, more preferably 85% or more, and even more preferably more than 90 percent. The impregnation ratio here refers to the ratio to which the reinforcing fiber group constituting the prepreg is impregnated with the resin. The impregnation rate can be obtained by measuring the proportion of the resin not impregnated by a specific method. The larger the impregnation ratio, the smaller the voids contained in the prepreg, and the higher the impregnation ratio is preferred from the viewpoints of the surface appearance of the obtained molded product and the further improvement of the mechanical properties. As a method of measuring the impregnation rate, in cross-sectional observation perpendicular to the fiber direction of the prepreg, the total cross-sectional area of the prepreg including the voids in the prepreg is defined as A0, and the cross-sectional area of the voids is defined as A0. When the area is set to A1, the following formula (1) is used to obtain the impregnation rate. Impregnation rate (%)=(A0-A1)×100/A0･･･(1)

The details of each requirement constituting the prepreg of the present invention will be described below.

＜Reinforcing fiber group＞ The reinforcing fiber group is an aggregate (fiber bundle) of reinforcing fibers, which may be any of continuous fibers and discontinuous fibers, and can be appropriately selected from: a form arranged in one direction and a laminated form thereof, or fabric type, etc. From the viewpoint of obtaining a lightweight and highly durable fiber-reinforced plastic, continuous fibers or fabrics in which reinforcing fibers are arranged in one direction are preferred. The fiber bundles may be composed of the same reinforcing fibers, or may be composed of different reinforcing fibers. The number of fibers constituting the reinforcing fiber bundle is not particularly limited, but 300 to 60,000 can be exemplified, but from the viewpoint of productivity, it is preferably 300 to 48,000, and more preferably 1,000 to 24,000.

The type of reinforcing fibers constituting the reinforcing fiber group is not particularly limited, for example, carbon fibers, glass fibers, polyaramid fibers, alumina fibers, silicon carbide fibers, boron fibers, metal fibers, natural fibers, mineral fibers, etc. can be used, These may be used in combination of 1 type or 2 or more types. Among them, it is preferable to use carbon fibers such as PAN (polyacrylonitrile)-based, pitch-based, and rayon-based carbon fibers from the viewpoint of the effect of high specific strength and specific rigidity and weight reduction. In addition, from the viewpoint of improving the economical efficiency of the obtained prepreg, it is preferable to use glass fiber, and in particular, from the viewpoint of the balance between mechanical properties and economical efficiency, it is preferable to use carbon fiber and glass fiber together. Furthermore, from the viewpoint of improving the impact absorption and formability of the obtained prepreg, polyaramide fibers can be preferably used, and in particular, the balance between mechanical properties and impact absorption is preferred. Combining carbon fiber and polyaramid fiber. In addition, from the viewpoint of improving the electrical conductivity of the obtained prepreg, reinforcing fibers or pitch-based carbon fibers coated with metals such as nickel, copper, or ytterbium may also be used.

From the viewpoint of improving mechanical properties, the reinforcing fibers constituting the reinforcing fiber group are preferably surface-treated with a sizing agent. Examples of sizing agents include polyfunctional epoxy resins, urethane resins, acrylic polymers, polyols, polyethyleneimine, ethylene oxide adducts of aliphatic alcohols, and the like. Specifically, For example: glycerol triglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, arabitol polyglycidyl ether, trimethylolpropane triglycidyl ether , polyglycidyl ethers of aliphatic polyols such as neotaerythritol polyglycidyl ether, polyacrylic acid, copolymers of acrylic acid and methacrylic acid, copolymers of acrylic acid and maleic acid, or mixtures of two or more of these, Polyvinyl alcohol, glycerin, diglycerol, polyglycerol, sorbitol, arabitol, trimethylolpropane, neotaerythritol, polyethyleneimine with more amine groups in one molecule, polyoxyethylene Oleyl ether, etc. Among these, glycerol triglycidyl ether and diglycerol polyglycidyl ether are preferably used from the viewpoint of containing a plurality of highly reactive epoxy groups in one molecule, high water solubility, and ease of application. , Polyglycerol polyglycidyl ether.

Moreover, as a reinforcement fiber, the surface free energy measured by the Wilhelmy method is 10-50 mJ/m< ² > is preferable. By controlling the surface free energy within this range, the affinity with both the thermosetting resin layer and the thermoplastic resin layer is improved, the aggregation of reinforcing fibers is suppressed, and the dispersibility in the layer is improved. As a result, in the thermoplastic resin layer The dispersed phase of the second thermosetting resin is more stably formed. In addition, the reinforcing fibers have high affinity with the thermosetting resin layer and the thermoplastic resin layer, and the reinforcing fibers are present across the interface between the thermosetting resin and the thermoplastic resin, and exhibit high bonding strength. The surface free energy of the reinforcing fiber is preferably 15 to 40 mJ/m ² , more preferably 18 to 35 mJ/m ² .

As a method of controlling the surface free energy of reinforcing fibers, there are a method of controlling the amount of an oxygen-containing functional group such as a carboxyl group or a hydroxyl group by subjecting the surface to an oxidation treatment, and a method of adhering a monomer or a plurality of compounds to the surface to control Methods. When a plurality of compounds are attached to the surface, the one with a higher surface free energy and one with a lower surface free energy may be mixed and attached. The calculation method of the surface free energy of the reinforcing fiber will be described below. The surface free energy can be calculated by the following method: After measuring the contact angles of the reinforcing fibers with respect to three solvents (purified water, ethylene glycol, and tricresyl phosphate), respectively, the surface free energy is calculated using the approximate formula of Owens. Although the calculation process is shown below, the measurement equipment and detailed methods are not limited to those described below.

Using DCAT11 manufactured by DataPhysics, first take out 1 fiber from the reinforcing fiber bundle, cut it into 8 pieces with a length of 12±2mm, and attach it to the special holder FH12 (surface in parallel with the distance between single fibers 2 to 3mm). Plates coated with adhesive substances). After that, the front ends of the single fibers were trimmed and set on the DCAT11 of the holder. Measurement system: The container containing each solvent was brought close to the lower end of the eight monofilaments at a speed of 0.2 mm/s, and immersed until 5 mm from the front end of the monofilament. After that, the single fiber was pulled up at a speed of 0.2 mm/s. Repeat this operation 4 more times. The force F on the single fiber when immersed in the liquid was measured with an electronic balance. Using this value, the contact angle θ was calculated by the following formula. COSθ=(F force F (mN) on 8 single fibers)/((8 (number of single fibers) × circumference of single fibers (m) × surface tension of solvent (mJ/m ² )) The measurement was performed on the single fibers pulled out from three different locations of the reinforcing fiber bundle. That is, the average value of the contact angles of a total of 24 single fibers for one reinforcing fiber bundle was obtained.

The surface free energy γ _f of the reinforcing fiber is calculated as the sum of the polar component γ ^p _f of the surface free energy and the nonpolar component γ ^d _f of the surface free energy. The polar component γ ^p _f of the surface free energy is obtained by the following method: Substitute the component of the surface tension of each liquid and the contact angle into the approximate formula of Owens shown in the following formula (from the polar component of the existing surface tension of each solvent) After X and Y are plotted with the non-polar component and the contact angle θ, the square of the slope a when a straight line is approximated by the least squares method is used to obtain it. The non-polar component γ ^d _f of the surface free energy is obtained by the square of the slice b. The surface free energy γ _f of the reinforcing fiber is the sum of the square of the slope a and the square of the slice b. Y=a･X+b X=√(The polar component of the surface tension of the solvent (mJ/m ² ))/√(The non-polar component of the surface tension of the solvent (mJ/m ² ) Y=(1+COSθ)‧ (Polar component of the surface tension of the solvent (mJ/m ² ))/2√(Non-polar component of the surface tension of the solvent (mJ/m ² ) Polar component of the surface free energy of the reinforcing fiber γ ^p _f =a ² Reinforcing fiber The non-polar component of the surface free energy γ ^d _f =b ² The total surface free energy γ _f =a ² +b ² . The polar and non-polar components of the surface tension of each solvent are as follows. ・The surface tension of purified water is 72.8mJ /m ² , polar component 51.0mJ/m ² , non-polar component 21.8(mJ/m ² ) ・Ethylene glycol surface tension 48.0mJ/m ² , polar component 19.0mJ/m ² , non-polar component 29.0(mJ/m ² ) ・The surface tension of tricresyl phosphate is 40.9 mJ/m ² , the polar component is 1.7 mJ/m ² , and the non-polar component is 39.2 (mJ/m ² ).

In addition, as for the reinforcing fiber bundle, if the tensile strength of the strand measured in accordance with the resin-impregnated strand (strand) test method of JIS R7608 (2007) is 3.5 GPa or more, it is possible to obtain a tensile strength that also has a Reinforced plastics with excellent bonding strength are preferred, and more preferably 4.0GPa or more. The joint strength referred to here refers to the tensile shear joint strength determined in accordance with ISO4587 (1995).

In the prepreg of the embodiment of the present invention, the content of the reinforcing fibers per unit area is preferably from 30 to 2,000 g/m ² , more preferably from 50 to 300g/m ² or less.

The mass content of the reinforcing fibers constituting the reinforcing fiber group in the prepreg is preferably 30 to 90 mass %, more preferably 35 to 85 mass %, still more preferably 40 to 80 mass %. If the mass content of the reinforcing fibers is within the preferred range, it is easy to obtain a molded product with better specific strength and specific elastic modulus.

<Thermosetting resin layer> The thermosetting resin layer can be formed by curing a thermosetting resin composition containing the first thermosetting resin as a main component. The first thermosetting resin may also contain additives and the like according to requirements.

The type of the first thermosetting resin is not particularly limited, and examples thereof include unsaturated polyester resins, vinyl ester resins, epoxy resins, phenol resins, urea resins, melamine resins, polyimide resins, cyanate ester resins, bismuth resins Lysimide resin, benzodiazepine resin, or these copolymers, modified bodies, and resins obtained by mixing at least two of these. In order to improve impact resistance, an elastomer or a rubber component may be added to the first thermosetting resin composition. Among them, epoxy resins are preferable because they are excellent in mechanical properties, heat resistance, and adhesion to reinforcing fibers.

As the main component of the epoxy resin, for example, bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, and bisphenol S type epoxy resin can be mentioned. , brominated epoxy resin such as tetrabromobisphenol A diglycidyl ether, epoxy resin with biphenyl skeleton, epoxy resin with naphthalene skeleton, epoxy resin with dicyclopentadiene skeleton, phenol novolac type Epoxy resin, cresol novolac epoxy resin and other novolak epoxy resin, N,N,O-triglycidyl-m-aminophenol, N,N,O-triglycidyl-o-aminophenol, N, N, N,O-Triglycidyl-4-amino-3-methylphenol, N,N,N',N'-tetraglycidyl-4,4'-methylenediphenylamine, N,N,N' ,N'-tetraglycidyl-2,2'-diethyl-4,4'-methylenediphenylamine, N,N,N',N'-tetraglycidyl-m-xylylenediamine, N , N-diglycidyl aniline, N, N-diglycidyl o-toluidine and other glycidyl amine epoxy resins, resorcinol diglycidyl ether, triglycidyl tripolyisocyanate and so on.

The first thermosetting resin composition may also contain a hardener. Examples of the curing agent in the first thermosetting resin composition include dicyandiamine, aromatic amine compounds, phenol novolac resins, cresol novolac resins, polyphenol compounds, imidazole derivatives, tetramethylguanidine, Thiourea addition amine, carboxylate hydrazide, carboxylate amide, polythiol, etc. Moreover, these hardeners are preferably 0.8 to 1.2 equivalents of the number of reactive functional groups of the first thermosetting resin.

Furthermore, in the first thermosetting resin composition, mica, talc, kaolinite, hydrotalcite, sericite, bentonite, tombstone, sepiolite, bentonite, montmorillonite, and silica may also be added according to the application. Limestone, silica, calcium carbonate, glass beads, glass flakes, glass microspheres, clay, molybdenum disulfide, titanium oxide, zinc oxide, antimony oxide, calcium polyphosphate, graphite, barium sulfate, magnesium sulfate, zinc borate, Fillers such as calcium borate, aluminum borate whiskers, potassium titanate whiskers, and polymer compounds, metals, metal oxides, materials imparting conductivity such as carbon black and graphite powder, halogens such as brominated resins Flame retardants, antimony-based flame retardants such as antimony trioxide or antimony pentoxide, phosphorus-based flame retardants such as ammonium polyphosphate, aromatic phosphate esters and red phosphorus, organoboric acid metal salts, carboxylate metal salts, and aromatic sulfonates Organic acid metal salt flame retardants such as imine metal salts, inorganic flame retardants such as zinc borate, zinc, zinc oxide and zirconium, cyanuric acid, isocyanuric acid, melamine, melamine polycyanate, Nitrogen-based flame retardants such as melamine phosphate and guanidine nitride, fluorine-based flame retardants such as PTFE, polysiloxane-based flame retardants such as polyorganosiloxane, and metal hydroxide-based flame retardants such as aluminum hydroxide or magnesium hydroxide flame retardants, as well as other flame retardants, cadmium oxide, zinc oxide, cuprous oxide, copper oxide, ferrous oxide, iron oxide, cobalt oxide, manganese oxide, molybdenum oxide, tin oxide and titanium oxide flame retardant additives , pigments, dyes, lubricants, mold release agents, compatibilizers, dispersants, crystallization nucleating agents such as mica, talc and kaolinite, plasticizers such as phosphate esters, heat stabilizers, antioxidants, anti-coloring agents, UV absorbing agents Agents, fluidity modifiers, foaming agents, antibacterial agents, anti-vibration agents, deodorants, sliding modifiers, and antistatic agents such as polyetheresteramides. Especially in the use of electricity. In the case of electronic equipment, automobiles, airplanes, etc., there are cases where flame retardancy is required, and it is preferable to add phosphorus-based flame retardants, nitrogen-based flame retardants, and inorganic-based flame retardants. While the above-mentioned flame retardant exhibits a flame retardant effect, in order to maintain a good balance of properties such as the mechanical properties of the resin used and the resin fluidity during molding, the amount of the flame retardant is preferably 1 to 100 parts by mass of the resin. 20 parts by mass, more preferably 1 to 15 parts by mass.

The volume of the reinforcing fibers contained in the thermosetting resin layer is preferably 50% of the total volume of the reinforcing fibers contained in the entire prepreg from the viewpoint of the balance between the mechanical properties of the resulting molded product and the weldability of the second member. ~99%, more preferably 75~95%.

The method for measuring the amount of reinforcing fibers in the thermosetting resin layer can be exemplified, for example, by performing a segmentation analysis using an X-ray CT image of a small piece of fiber-reinforced plastic obtained by curing the prepreg. The volume of the existing reinforcing fibers divided by the total volume of the reinforcing fibers contained in the above-mentioned small pieces to obtain the ratio [%]; or from an optical microscope, a scanning electron microscope (SEM) or a transmission electron microscope (TEM) ) A method of obtaining the ratio [%] by dividing the area of the reinforcing fibers present in the thermosetting resin layer by the area of the reinforcing fibers contained in the entire small piece in the image obtained by observing the cross section of the small piece. During the observation, in order to adjust the contrast, the thermosetting resin layer and/or the thermoplastic resin layer may also be dyed.

<Thermoplastic resin layer> The thermoplastic resin layer is not particularly limited except for the dispersed phase containing the second thermosetting resin, and can be formed using a thermoplastic resin composition containing a thermoplastic resin as a main component. The thermoplastic resin composition may also contain additives and the like according to requirements.

The type of the thermoplastic resin as the main component of the thermoplastic resin layer is not particularly limited, and examples thereof include "polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyterephthalate Polyester such as propylene dicarboxylate (PTT), polyethylene naphthalate (PEN), liquid crystal polyester, or polyolefin such as polyethylene (PE), polypropylene (PP), polybutene, or Polyoxymethylene (POM), polyamide (PA), polyphenylene sulfide (PPS) and other polyarylene sulfide, polyketone (PK), polyetherketone (PEK), polyetheretherketone (PEEK), polyarylene ether Crystalline resins such as ketone (PAEK), polyetherketoneketone (PEKK), polyethernitrile (PEN), polytetrafluoroethylene and other fluorine-based resins; Methyl methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene ether (PPE), polyimide (PI), polyimide (PAI), polyetherimide (PEI), Amorphous resins such as poly (PSU), polyether, polyarylate (PAR)"; other phenolic resins, phenoxy resins; and polystyrene, polyolefin, polyurethane polyamides, polyesters, polyamides, polybutadienes, polyisoprenes, fluorine resins; thermoplastic elastomers such as acrylonitrile, etc.; selected thermoplastic resins. Among them, from the viewpoint of the lightness of the obtained prepreg, polyolefin is preferable. Also, from the viewpoint of strength, polyamide is preferred. In addition, from the viewpoint of heat resistance, polyarylene sulfide such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyaryl ether ketone (PAEK), and polyether ketone ketone (PEKK) are preferable.

Furthermore, in the thermoplastic resin composition, mica, talc, kaolinite, hydrotalcite, sericite, bentonite, dolmenite, sepiolite, bentonite, montmorillonite, wollastonite can also be added according to the application. , silica, calcium carbonate, glass beads, glass flakes, glass microspheres, clay, molybdenum disulfide, titanium oxide, zinc oxide, antimony oxide, calcium polyphosphate, graphite, barium sulfate, magnesium sulfate, zinc borate, bismuth borate Fillers such as calcium, aluminum borate whiskers, potassium titanate whiskers, and polymer compounds, metals, metal oxides, materials imparting conductivity such as carbon black and graphite powder, halogen-based flame retardants such as brominated resins antimony-based flame retardants such as antimony trioxide or antimony pentoxide, phosphorus-based flame retardants such as ammonium polyphosphate, aromatic phosphate esters and red phosphorus, organoboric acid metal salts, carboxylate metal salts and aromatic sulfonimides Organic acid metal salt flame retardants such as metal salts, inorganic flame retardants such as zinc borate, zinc, zinc oxide and zirconium, cyanuric acid, isocyanuric acid, melamine, melamine polycyanate, melamine phosphoric acid Nitrogen-based flame retardants such as esters and guanidine nitride, fluorine-based flame retardants such as PTFE, polysiloxane-based flame retardants such as polyorganosiloxane, and metal hydroxide-based flame retardants such as aluminum hydroxide or magnesium hydroxide , and other flame retardants, cadmium oxide, zinc oxide, cuprous oxide, copper oxide, ferrous oxide, iron oxide, cobalt oxide, manganese oxide, molybdenum oxide, tin oxide and titanium oxide flame retardant additives, pigments , dyes, lubricants, mold release agents, compatibilizers, dispersants, crystal nucleating agents such as mica, talc and kaolinite, plasticizers such as phosphate esters, heat stabilizers, antioxidants, anti-coloring agents, UV absorbers, Fluidity modifier, foaming agent, antibacterial agent, shock inhibitor, deodorant, sliding modifier, and antistatic agent such as polyetheresteramide, etc. Especially in the use of electricity. In the case of electronic equipment, automobiles, airplanes, etc., there are cases where flame retardancy is required, and it is preferable to add phosphorus-based flame retardants, nitrogen-based flame retardants, and inorganic-based flame retardants. While the above-mentioned flame retardant exhibits a flame retardant effect, in order to maintain a good balance of properties such as the mechanical properties of the resin used and the resin fluidity during molding, the amount of the flame retardant is preferably 1 to 100 parts by mass of the resin. 20 parts by mass, more preferably 1 to 15 parts by mass

The basis weight of the thermoplastic resin layer in the prepreg is preferably 10 g/m 2 or more and 500 g/m ² or less, more preferably 10 g/m ² or more, from the viewpoint of securing an amount of resin suitable for welding with the second member and improving quality. 20g/m ² or more and 200g/m ² or less. Here, the basis weight means the mass (g) of the thermoplastic resin layer contained per 1 m ² of the prepreg.

In addition, the thermoplastic resin layer may exist as a part of the surface layer of the fiber-reinforced plastic. The thermoplastic resin layer existing on the surface layer of the prepreg also forms the thermoplastic resin layer in the molded article obtained by molding the prepreg, and the thermoplastic resin layer can be welded to the second member to achieve integration. In this aspect, the portion of the thermoplastic resin layer can be kept to a minimum, and the productivity of the prepreg and the fiber-reinforced plastic can be improved.

<Second thermosetting resin> The second thermosetting resin has, as a main component, a thermosetting resin that does not dissolve in the thermoplastic resin to form a dispersed phase and can be in contact with the reinforcing fibers. In addition, in order to improve the adhesive strength without impairing the toughness of the thermoplastic resin layer, it is preferable to select a thermosetting resin with high toughness. Moreover, an additive etc. may be contained according to the application of a fiber-reinforced plastic. Specifically, the same resin as the first thermosetting resin can be exemplified.

The second thermosetting resin and the first thermosetting resin are the same kind of resin, and are more preferably the same resin from the viewpoint of easy setting of conditions in the molding of the prepreg and the welding of the molded product. In addition, in the present invention, "the same kind" means that the main components other than additives and the like are the same. Similarly, the cured product of the second thermosetting resin is preferably the same type, and more preferably the same, as the cured product of the first thermosetting resin composition forming the thermosetting resin layer.

Regarding the curing agent and additives that can be contained in the second thermosetting resin, the same specific examples as the curing agent and additives that can be contained in the first thermosetting resin layer can be given, and the preferred examples are also the same.

<Manufacturing method of prepreg> As a method for producing the prepreg of the present invention, for example, a method for producing a prepreg comprising the steps of impregnating the second thermosetting resin precursor on one side of the reinforcing fiber sheet constituting the reinforcing fiber group can be exemplified, Steps of impregnating the reinforcing fiber sheet with the precursor of the thermoplastic resin layer to form a dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer; and impregnating the other side surface of the reinforcing fiber sheet with the precursor of the thermosetting resin layer , and the step of forming the thermosetting resin layer.

Alternatively, there can be exemplified a method for producing a prepreg comprising the steps of impregnating one side surface of the reinforcing fiber sheet constituting the reinforcing fiber group with a thermoplastic resin precursor, and then impregnating the reinforcing fiber with the precursor of a thermosetting resin layer. A step of forming a disperse phase of the second thermosetting resin by heating and pressing the interface region between the thermoplastic resin and the thermosetting resin while forming the sheet, so that a part of the thermosetting resin is contained in the thermoplastic resin layer.

Also, a method for producing a prepreg comprising the steps of: impregnating both sides of the reinforcing fiber sheet constituting the reinforcing fiber group with a precursor of a thermosetting resin layer to form a thermosetting resin layer; and forming a thermosetting resin layer on at least one side of the thermosetting resin layer softening or melting the precursor of the thermoplastic resin layer and applying pressure to mix the precursor of the thermosetting resin layer with the precursor of the thermoplastic resin layer to form a dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer step.

Furthermore, in this step, a shear force is applied by applying pressure and vibrating the precursor of the thermosetting resin layer and the precursor of the thermoplastic resin layer during mixing. Thereby, the mixing of the thermoplastic resin layer and the thermosetting resin layer is facilitated, and the formation of the dispersed phase of the thermosetting resin is promoted. In addition, by complicating the interface formed by the thermoplastic resin layer and the thermosetting resin layer, in addition to enhancing the effect of the present invention, the weldability of the fiber-reinforced plastic can be enhanced. From this point of view, it is preferable to use this example. . As a method of applying vibration, any one of the thermoplastic resin layer, the thermosetting resin layer, and the reinforcing fiber may be subjected to a shearing force, and an ultrasonic vibrator, a fixed rod that moves back and forth, and the like that perform periodic motion can be exemplified. device, as a mechanism for implementation.

As the temperature at which the precursor of the thermoplastic resin layer is melted, when the thermoplastic resin as the main component of the precursor of the thermoplastic resin layer is crystalline, it is preferable to perform heat/pressure molding at a temperature of its melting point + 30°C or more, In the case of being amorphous, it is preferable to heat and press-form at a glass transition temperature of +30° C. or higher.

As a method of forming the dispersed phase of the second thermosetting resin in contact with the reinforcing fibers contained in the thermoplastic resin layer of the prepreg, any of the following methods (i) to (v) can be mentioned, for example. These steps can be combined in various ways, and are not limited to these methods. (i) The step of making the thermoplastic resin layer precursor contain the dispersed phase precursor of the second thermosetting resin contained in the thermoplastic resin layer. (ii) on a prepreg intermediate obtained by impregnating a thermosetting resin layer precursor with a reinforcing fiber sheet constituting a reinforcing fiber group, applying a dispersed phase precursor of the second thermosetting resin contained in the thermoplastic resin layer, and then The step of impregnating the thermoplastic resin layer with the precursor. (iii) The thermoplastic resin layer is coated with a dispersion-phase precursor of the second thermosetting resin contained in the thermoplastic resin layer on the prepreg intermediate obtained by impregnating the reinforcing fiber group with the thermoplastic resin layer precursor, and then the thermoplastic resin layer is A step containing a dispersed phase. (iv) Impregnating a thermoplastic resin layer precursor with a prepreg intermediate obtained by impregnating a thermosetting resin precursor with a reinforcing fiber sheet constituting a reinforcing fiber group, and applying pressure to the thermoplastic resin to cause the thermoplastic resin layer to contain The step of thermosetting resin to form the dispersed phase. (v) With respect to the prepreg intermediate obtained by impregnating the reinforcing fiber group with the thermoplastic resin layer precursor and the thermosetting resin layer precursor, shear force is applied by applying a vibrating device or the like to form a prepreg contained in the thermoplastic resin layer The step of dispersing the thermosetting resin.

<Precursor of thermosetting resin layer> The thermosetting resin layer precursor is a composition that impregnates the reinforcing fiber group and becomes the thermosetting resin layer. The method of impregnating the reinforcing fiber group with the precursor of the thermosetting resin layer is not particularly limited, and examples thereof include a method of softening or melting by heating and pressing with a hot roll, and impregnating it. The form of the precursor of the thermosetting resin layer is not limited, and examples thereof include liquid form, sheet form, non-woven fabric form, particle form, and the like, and from the viewpoint of uniformly impregnating the reinforcing fiber group, sheet form is preferred.

<Precursor of thermoplastic resin layer> The thermoplastic resin layer precursor is a composition (thermoplastic resin composition) that is impregnated with the reinforcing fiber group to become the thermoplastic resin layer. The method of impregnating the reinforcing fiber group with the precursor of the thermoplastic resin layer is not particularly limited, and for example, a method of impregnating the thermoplastic resin layer by melting and applying heat and pressure with a hot roll may be mentioned. The form of the thermoplastic resin layer precursor is not limited, and examples thereof include liquid form, sheet form, non-woven fabric form, and particulate form. From the viewpoint of uniformly impregnating the reinforcing fiber group, sheet form or non-woven fabric form is preferred.

The thermoplastic resin layer precursor may be disposed on a part of the surface layer of the prepreg from the viewpoint of ensuring stable thermal fusion properties. That is, the thermoplastic resin layer should just be arranged in the part which becomes the joint surface with a 2nd member when shaping|molding a prepreg as a molded product. From the viewpoint of leaving a margin for the joint surface, the thermoplastic resin layer is preferably arranged on 50% or more of the surface area, and more preferably 80% or more.

<Precursor of the dispersed phase of the second thermosetting resin> The precursor of the dispersed phase of the second thermosetting resin can be used, for example, in a liquid, sheet, nonwoven, or granular form, and is preferably in a granular form from the viewpoint of forming a dispersed phase in the thermoplastic resin layer.

In the case where the precursor of the dispersed phase of the second thermosetting resin is contained in the precursor of the thermoplastic resin layer in advance, that is, in the case of having the above-mentioned step (i), from the viewpoint of the step stability of the prepreg, the thermoplastic resin layer is more stable than the thermoplastic resin layer. For 100 parts by mass of the precursor of the resin layer, the precursor of the dispersed phase of the second thermosetting resin is preferably in the range of 10 to 40 parts by mass, more preferably in the range of 15 to 40 parts by mass, and even more preferably in the range of 25 to 40 parts by mass range of copies.

＜Fiber Reinforced Plastic＞ Another aspect of the present invention is a fiber-reinforced plastic comprising: a reinforcing fiber group containing reinforcing fibers, a thermosetting resin layer containing a first thermosetting resin, and a thermoplastic resin layer, wherein, having the aforementioned thermoplastic resin layer as the surface layer of the aforementioned fiber-reinforced plastic, The interface between the thermoplastic resin layer and the thermosetting resin layer is located inside the reinforcing fiber group, The aforementioned thermoplastic resin layer includes a dispersed phase of the second thermosetting resin.

As an embodiment of the fiber-reinforced plastic of the present invention, a molded body obtained by molding the prepreg of the present invention, that is, a form in which the first and second thermosetting resins constituting the prepreg are cured can be exemplified. . In addition, the fiber-reinforced plastic can be formed by forming the above-mentioned prepreg alone, or by laminating a plurality of sheets thereof, or by laminating and forming with other materials. The structure of the laminate is not particularly limited as long as the prepreg of the present invention is arranged on any laminate unit located on the outermost side of the surface of the molded product, and prepregs, films, sheets, and non-woven fabrics can be laminated according to the application. , porous bodies, metals, etc.

1 is a schematic diagram of cutting a part of the surface of the fiber reinforced plastic according to the embodiment of the present invention to obtain a cross section perpendicular to the plane, that is, the present invention can be presented by observing at least one cross section of the fiber reinforced plastic. The surface of the fiber-reinforced plastic of the embodiment of the present invention is the same as that of the prepreg of the embodiment of the present invention, and can be described with reference to FIG. 1 . That is, the reinforcing fiber group 12 containing the reinforcing fibers 1 and 14, the thermosetting resin layer 2 containing the first thermosetting resin, and the thermoplastic resin layer 3 are included, wherein the surface layer of the fiber-reinforced plastic is the thermoplastic resin layer 3, and the thermoplastic resin layer 3 and the thermoplastic resin layer 3. The interface of the thermosetting resin layer 2 is located inside the reinforcing fiber group 12 , and the thermoplastic resin layer 3 contains the dispersed phase 4 of the second thermosetting resin.

The dispersed phase 4 in the fiber-reinforced plastic of the embodiment of the present invention is the same as that of the prepreg of the present invention, and refers to the part of the thermoplastic resin layer observed in the cross-section perpendicular to the plane of the fiber-reinforced plastic. A separate area of hardened thermoset resin. That is, in the molding of the prepreg of the present invention, since the dispersed phase 4 binds the reinforcing fibers and suppresses the flow of the thermoplastic resin layer, only the hardening reaction of the thermosetting resin is promoted, and the same can be maintained as in the description of the prepreg above. The reinforcing fiber, thermoplastic resin layer, thermosetting resin layer and second thermosetting resin layer.

Therefore, in the fiber-reinforced plastic of the embodiment of the present invention, the plurality of reinforcing fibers contained in the thermoplastic resin layer and the dispersed phase of the second thermosetting resin are brought into contact, so that the plurality of reinforcing fibers can be regarded as being partially bonded to each other, When the molded product is welded, even if the thermoplastic resin layer is in a fluid state due to high temperature conditions, the orientation disorder and movement of the reinforcing fibers can be suppressed, the thermoplastic resin layer can be prevented from flowing out excessively, and the thickness of the thermoplastic resin layer to be the adhesive layer can be ensured. , which helps to improve the quality.

Similarly, the shape of the dispersed phase of the second thermosetting resin is not particularly limited as long as it is an independent region. For example, in a cross-section perpendicular to the plane, when the cross-section of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer is observed, it can be a fibrous, circular, oval, rectangular, or complex shape with irregularities.

The major axis length of the dispersed phase of the second thermosetting resin is also the same, and is preferably 50 nm or more, more preferably 100 nm or more, still more preferably 300 nm or more, and still more preferably 1 μm or more. By setting the major axis length of the dispersed phase of the second thermosetting resin within this range, the flow of the thermoplastic resin layer can be effectively suppressed under high temperature conditions during welding, thereby ensuring higher quality.

Similarly, in the fiber-reinforced plastic of the embodiment of the present invention, the dispersion of the second thermosetting resin contained in the thermoplastic resin layer relative to 100% by volume of the thermoplastic resin layer in the reinforcing fiber group in the thickness direction cross section The volume ratio of the phase may be at least 1% by volume, more preferably at least 10% by volume, and even more preferably at least 15% by volume.

The volume ratio of the dispersed phase of the second thermosetting resin to 100% by volume of the reinforcing fibers contained in the thermoplastic resin layer is from the viewpoint of the balance between the effect of suppressing the flow of the thermoplastic resin during welding and not impairing the high toughness of the plastic resin , preferably not less than 3% by volume and not more than 50% by volume.

Similarly, the dispersed phase of the second thermosetting resin is preferably biased toward the thermoplastic resin layer near the interface between the thermosetting resin layer and the thermoplastic resin layer rather than uniformly dispersed in the thermosetting resin layer.

Specifically, in the cross section in the thickness direction of the fiber-reinforced plastic, when the area of 50 μm from the interface between the thermoplastic resin layer and the thermosetting resin layer toward the surface of the thermoplastic resin layer in the cross section in the thickness direction is taken as 100% by volume, the amount of The sum of the volume ratios of the contained reinforcing fibers and the second thermosetting resin is preferably 10% by volume or more, more preferably 30% by volume or more. Moreover, the sum of the volume ratios is preferably 90% by weight or less, more preferably 70% by volume or less.

(Interface between thermosetting resin layer and thermoplastic resin layer) Similarly, in the fiber-reinforced plastic of the embodiment of the present invention, the interface between the thermosetting resin layer and the thermoplastic resin layer is located inside the reinforcing fiber group.

The elements constituting the fiber-reinforced plastic according to the embodiment of the present invention, that is, the reinforcing fibers or groups of reinforcing fibers, the thermoplastic resin, the thermosetting resin, and the second thermosetting resin, are the same as those in the prepreg of the present invention, and are more The optimal range is also the same. In addition, various observation methods and analysis methods are also the same as the specific examples described above in the prepreg of the present invention.

Here, in the fiber-reinforced plastic according to the embodiment of the present invention, from the viewpoint of maintaining the bonding of the plurality of fibers in the thermoplastic resin layer under the high temperature conditions at the time of welding with the second member, the second thermosetting resin The glass transition temperature is preferably 150°C or higher, more preferably 180°C or higher. As the analysis method of the second thermosetting resin and the first thermosetting resin contained in the thermosetting resin layer, the method of analyzing the glass transition temperature obtained by the differential scanning calorimeter (DSC), the method of analyzing the glass transition temperature obtained by the differential scanning calorimeter (DSC), the method of analyzing the A method of analyzing an elemental analysis distribution image obtained by a radiation spectrometer (EDS), and a method of analyzing an elastic coefficient obtained by a nano-scratch method.

The fiber-reinforced plastic as an embodiment of the present invention is not limited to an example in which the prepreg, which is an embodiment of the present invention, is molded, as long as the prepreg is molded by autoclave, press molding, drawing, resin, etc. The process of transfer injection molding (RTM) and resin infiltration (RI) molding as the embodiment of the present invention can be preferably selected. The structure of the fiber reinforced plastic of the embodiment of the present invention is not particularly limited, and various structures such as a flat plate or a curved plate, a concave-convex structure, a hollow structure, and a sandwich structure can be selected according to the application. Generally speaking, it is better to use a prepreg when a flat structure with high mechanical properties is required, and it is better to use RTM when a complex three-dimensional structure is required.

＜Integrated molding product＞ The one-piece molded product of the embodiment of the present invention is formed by allowing the first member including the fiber-reinforced plastic of the embodiment of the present invention to pass through the thermoplastic resin layer disposed on the surface layer of the fiber-reinforced plastic and the second member including other structural members. An integrally formed product that is joined together. In the one-piece molded product of the embodiment of the present invention, the distance t between the thermosetting resin layer of the fiber-reinforced plastic and the second member is larger than the long axis length of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer, so as to ensure the welding From the viewpoint of the quality stability of the bonding strength, it is preferably 10 μm or more and 200 μm or less, and more preferably 30 μm or more and 100 μm or less.

The method of joining the first member and the second member is not limited, but for example, welding such as hot plate welding, vibration welding, ultrasonic welding, laser welding, resistance welding, induction welding, insert injection molding, and outsert injection molding can be mentioned. Law.

The fiber-reinforced plastic and the integrally formed product of the present invention can be preferably used for computer applications such as aircraft structural components, windmill blades, automobile outer panels, IC trays or notebook computer casings, and can also be used for golf clubs and nets. Racket and other sports use. [Example]

Hereinafter, the present invention will be described in more detail by way of examples. However, the scope of the present invention is not limited to these embodiments. In addition, the measurement of various characteristics was performed in the environment of 23 degreeC, 50% relative humidity unless otherwise specified.

<Reinforcing fiber bundle> - Reinforcing fiber bundle 1 Spinning, firing treatment, and surface oxidation treatment of a copolymer containing polyacrylonitrile as a main component were performed to obtain a reinforcing fiber bundle 1 containing continuous carbon fibers with a total number of 24,000 single yarns. It is used for the formation of reinforcing fiber clusters. The properties of this reinforcing fiber bundle 1 are as follows. Single fiber diameter: 7μm Density: 1.8g/cm ³ Tensile strength: 4.2GPa Tensile elastic coefficient: 230GPa Surface free energy: 15mJ/m ²

・Reinforcing fiber bundle 2 Using the reinforcing fiber 1 as a matrix, various sizing agent compounds and acetone were mixed to obtain a solution of about 1 mass % in which the compounds were uniformly dissolved. After applying each compound to the carbon fiber bundle by the dipping method, heat treatment was performed at 210° C. for 90 seconds, and the adhesion amount of each compound was adjusted to 0.5 parts by mass relative to 100 parts by mass of carbon fibers to which each compound adhered. The compound for a sizing agent used for each carbon fiber and the surface free energy after coating with the sizing agent are as follows.・Reinforcing fiber bundle 2-1 Bisphenol A diglycidyl ether (“jER” (registered trademark) 828, manufactured by Mitsubishi Chemical Co., Ltd.) Surface free energy: 9 mJ/m ²・Reinforcing fiber bundle 2-2 Polyethylene Glycol diglycidyl ether ("Denacol" (registered trademark) EX-841, manufactured by Nagase Chemtex Co., Ltd.) Surface free energy: 20 mJ/m ²・ Reinforcing fiber bundle 2-3 Sorbitol polyglycidyl ether ("Denacol" (registered trademark) EX-614B, manufactured by Nagase Chemtex Co., Ltd.) Surface free energy: 32 mJ/m ²

<Thermosetting resin composition> ・Thermosetting resin composition 1 50 parts by mass, 50 parts by mass, and 7 parts by mass of epoxy resin main ingredients (Araldite (registered trademark) MY721 (manufactured by Huntsman Advanced Materials Co., Ltd.)) and (jER (registered trademark) 825 (Mitsubishi Chemical) were put into the kneading device, respectively. Co., Ltd.)) and (Sumikaexcel (registered trademark) PES5003P (manufactured by Sumitomo Chemical Co., Ltd.)) were heated and kneaded at 150° C. until each component was compatible. Next, after the temperature was lowered to 80° C. in a state where the kneading was continued, 45.1 parts by mass of a hardener (SEIKACURE-S, (manufactured by Wakayama Seika Kogyo Co., Ltd.)) was put in and kneaded at 80° C. for 30 minutes to obtain a Thermosetting resin composition 1.

・Thermosetting resin composition 2 50 parts by mass, 50 parts by mass and 7 parts by mass of epoxy resin main ingredients (jER (registered trademark) 825 (manufactured by Mitsubishi Chemical Co., Ltd.)) and (jER (registered trademark) 154 (Mitsubishi Chemical Co., Ltd.)) were put into the kneading device, respectively. Chemical Co., Ltd.)) and (Sumikaexcel (registered trademark) PES5003P (Sumitomo Chemical Co., Ltd.)) were heated and kneaded at 150° C. until each component was compatible. Next, after the temperature was lowered to 80° C. in the state where the kneading was continued, 6.8 parts by mass of a hardener (DICY7, (manufactured by Mitsubishi Chemical Co., Ltd.)) was put in and kneaded at 60° C. for 30 minutes to obtain a thermosetting resin composition. thing 2.

<Measurement method of glass transition temperature of thermosetting resin cured product> The thermosetting resin composition prepared by the above method was injected into the mold, heated from 30°C to the temperature listed in Table 1 at a rate of 1.5°C/min in a hot air dryer, and heated and hardened at the curing time described in Table 1, and then heated at a rate of 2.5°C. The temperature was lowered to 30°C per minute, and a plate-shaped resin cured product with a thickness of 2 mm was produced. A test piece with a width of 12.7 mm and a length of 45 mm was cut out from the produced plate-shaped resin cured product, and the test piece was dried in a vacuum oven at 60°C for 24 hours. A storage elastic coefficient curve was obtained from the elastic test. In this storage elastic coefficient curve, the temperature value at the intersection of the tangent in the glass state and the tangent in the transition state was taken as the glass transition temperature. Here, the measurement was performed at a temperature increase rate of 5°C/min and a frequency of 1 Hz.

<Thermoplastic resin composition> ・Thermoplastic resin composition 1 Low melting point polyamide (AMILAN (registered trademark) CM4000 (manufactured by Toray Co., Ltd.), 3-membered copolymer polyamide resin, melting point 155°C)

・Thermoplastic resin composition 2 Polyamide 6 (AMILAN (registered trademark) CM1007 (manufactured by Toray Co., Ltd., melting point 225°C))

・Thermoplastic resin composition 3 Polyphenylene sulfide (TORELINA (registered trademark) A670T05 (manufactured by Toray Co., Ltd.), melting point 278°C)

・Thermoplastic resin composition 4 Polyetherketoneketone (Kepstan (registered trademark) 7002 (manufactured by ARKEMA Co., Ltd.), melting point 332°C)

<Evaluation method of thermoplastic resin> The melting point of the thermoplastic resin is measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121 (2012). When a plurality of melting points are observed in a mixture or the like, the highest melting point is adopted as the melting point of the thermoplastic resin.

<Cross-sectional observation of prepreg or fiber-reinforced plastic> In the prepreg or fiber-reinforced plastic, a cross-section cut in the thickness direction at an angle perpendicular to the fiber direction of the outermost layer is photographed with an optical microscope at a magnification of 1000 times. For the prepreg, an image was obtained in the same manner as described above from a cross-section cut out from a person hardened in an unloaded state.

(1) Obtaining the profile curve As shown in FIG. 3 , in an arbitrary 300 μm-square observation range in the obtained image, a cross-sectional curve was obtained by the following method. Using the end 100 of the rectangular observation image 9 on the thermoplastic resin layer 3 side as a reference line, a vertical line 120 is drawn every 5 μm from the thermoplastic resin layer 3 toward the thermosetting resin layer 2 . The point at which the vertical line drawn from the reference line intersects the thermosetting resin layer 2 for the first time is marked, and the line formed by connecting the marked points is used as the profile curve 130 .

(2) Analysis of thermoplastic resin layer 1 In an arbitrary 300 μm-square observation range in the obtained image, the dispersed phase of the second thermosetting resin in contact with the reinforcing fibers contained in the thermoplastic resin layer was found, and its size was measured. The size is the value of the long axis of the dispersed phase of the second thermosetting resin. In addition, the long axis of the disperse phase of the second thermosetting resin is the distance between the lines passing through the inside of the disperse phase of the second thermosetting resin confirmed in the above-mentioned cross-sectional observation image and passing through the outer periphery of the disperse phase of the second thermosetting resin. For the line segment at the farthest 2 points, if the disperse phase of the second thermosetting resin is less than 20, take the average value for all measurement lengths, and take the average value for 20 randomly selected measurement lengths when there are more than 20 points. .

(3) Analysis of thermoplastic resin layer 2 The area S0 of the thermoplastic resin layer in the reinforcing fiber group and the area S1 of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer were calculated in an arbitrary 300 μm square observation range in the obtained image. Here, a vertical line is drawn every 10 μm from the thermoplastic resin layer toward the thermosetting resin layer, and is divided into segments with the end portion on the thermoplastic resin layer side as a reference line. In this section, the reinforcing fibers closest to the reference line are marked, and the line formed by connecting the marked points is defined as the boundary line of the reinforcing fiber group, which is defined as the area of the thermoplastic resin layer in the reinforcing fiber group . The obtained S1 is divided by S0, and it is taken as the volume ratio A (volume %) of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer with respect to the thermoplastic resin layer in the reinforcing fiber group.

(4) Analysis of thermoplastic resin layer 3 The area S2 of the reinforcing fiber contained in the thermoplastic resin layer and the area S3 of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer were calculated in an arbitrary 300 μm-square observation range in the obtained image. The obtained S3 is divided by S2 to be used as the volume ratio B (volume %) of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer to the reinforcing fibers contained in the thermoplastic resin layer.

(5) Analysis of thermoplastic resin layer 4 In an arbitrary 300 μm-square observation range in the obtained image, an area of 50 μm from the cross-sectional curve toward the surface side of the thermoplastic resin layer was obtained, and the area S4 was calculated. The area S5 of the dispersed phase of the reinforcing fiber and the second thermosetting resin contained in the area of 50 μm was calculated. The obtained S5 is divided by S4, and it is regarded as the sum of the volume ratio (volume %) of the reinforcing fibers and the second thermosetting resin contained in the thermoplastic resin layer near the cross-sectional curve relative to the thermoplastic resin layer near the cross-sectional curve.

<Weldability evaluation of fiber-reinforced plastics> The fiber-reinforced plastic was cut into a shape with a width of 100 mm and a length of 100 mm with the direction whose angle was 0° with respect to the fiber direction of the contained reinforcing fibers as the longitudinal direction of the test piece, and dried in a vacuum oven for 24 hours. After that, the cut fiber-reinforced plastic was placed on a heat-resistant glass plate, and at a temperature 20°C higher than the melting point of the thermoplastic resin composition, the pressure was 3 MPa and kept for 1 minute, thereby obtaining a heat-resistant glass plate. member. The fiber-reinforced plastic was observed from the heat-resistant glass plate side, and the area S6 of the thermoplastic resin composition was calculated. The rate of change P of the projected area of the thermoplastic resin composition was obtained by dividing the obtained S6 by the area of the fiber-reinforced plastic, and the results were evaluated in the following manner. Less than 1.2: A 1.2 or more and less than 1.5: B 1.5 and above: C

<Measurement of the thickness of the adhesive layer of the integrally molded product> The fiber-reinforced plastic was cut into a shape with a width of 100 mm and a length of 100 mm with the direction whose angle was 0° with respect to the longitudinal direction of the reinforcing fibers contained as the longitudinal direction of the test piece, and dried in a vacuum oven for 24 hours. The cut fiber-reinforced plastic was placed in contact with an aluminum alloy member, and was pressurized at 3 MPa at a temperature 20°C higher than the melting point of the thermoplastic resin composition for 1 minute to obtain an integrally molded product. The cross-section obtained by cutting the joint portion of the obtained integrally formed product was photographed at a magnification of 1000 using an optical microscope. In an arbitrary 300 μm-square observation range in the obtained image, a profile curve was acquired by the same method as the above-mentioned <method of acquiring profile curve>. A vertical line is drawn from the fiber-reinforced plastic side surface of the aluminum alloy member toward the fiber-reinforced plastic side, and the distance until it intersects the profile curve is obtained. The aforementioned treatment was repeated 20 times in total, and the average value was taken to evaluate the thickness of the adhesive layer of the integrally molded product.

(Example 1) A reinforcing fiber sheet (basic weight 193 g/m ² ) in which the reinforcing fiber bundles 1 were aligned in one direction and fiber-opened to form a continuous reinforcing fiber group traveled in one direction, and contained as thermoplastic The thermoplastic resin composition 2 of the precursor of the resin layer is a non-woven resin sheet with a basis weight of 120 g/m ² , which is arranged on the reinforcing fiber sheet, and heated with an IR heater to partially melt the thermoplastic resin composition 2 and make it adhere to the reinforcing fiber sheet. One side of the fiber sheet is pressed with a roll whose surface temperature is kept below the melting point of the thermoplastic resin composition 2, and the sheet impregnated with the reinforcing fiber sheet is cooled to obtain a prepreg intermediate. Using a knife coater, the thermosetting resin composition 1 as the precursor of the thermosetting resin layer was coated on a release paper with a resin basis weight of 100 g/m ² to produce a thermosetting resin film, and then the thermosetting resin film was superposed on the intermediate body. On the other surface on which the thermoplastic resin composition 2 is impregnated, the thermosetting resin composition 1 is impregnated with the intermediate body while being heated and pressurized by a hot roll, and the thermoplastic resin composition 2 is completely melted to obtain a prepreg 1 . At this time, the thermoplastic resin layer was formed after the thermosetting resin was incorporated into the unmelted nonwoven fabric portion, and thus the properties of the prepreg 1 are shown in Table 2.

(Example 2) A prepreg 2 was obtained in the same manner as in Example 1, except that the thermosetting resin composition 2 and the thermoplastic resin composition 1 were used. The properties of the prepreg 2 are shown in Table 2.

(Example 3) A reinforcing fiber sheet (basic weight: 193 g/m ² ) in which the reinforcing fiber bundles 1 are aligned in one direction and fiber-opened to form a continuous reinforcing fiber group is made to run in one direction, and a thermosetting resin The composition 1 is freeze-pulverized, the obtained particles are dispersed on one side of the reinforcing fiber sheet, and the particles containing the curable resin composition 1 heated by an IR heater are impregnated with the reinforcing fibers as a precursor of the dispersed phase of the second thermosetting resin near the surface of the sheet. Furthermore, a film-like resin sheet having a basis weight of 120 g/m ² containing the thermoplastic resin composition 2 as the precursor of the thermoplastic resin layer was arranged on the same surface as the surface on which the above-mentioned particles were dispersed in the reinforcing fiber sheet, so that The IR heater is heated to melt the thermoplastic resin composition 2 and make it adhere to the entire surface of one side of the reinforcing fiber sheet, pressurized with a roll whose surface temperature is kept below the melting point of the thermoplastic resin composition 2, and then impregnate the reinforcing fiber The sheet was cooled to obtain a prepreg intermediate. Using a knife coater, the thermosetting resin composition 1 as the precursor of the thermosetting resin layer was coated on a release paper with a resin basis weight of 100 g/m ² to produce a thermosetting resin film, and then the above-mentioned thermosetting resin film was superposed on the above-mentioned intermediate body On the surface on the opposite side to which the thermoplastic resin composition 1 was impregnated, the intermediate body was impregnated with the thermosetting resin composition 1 while being heated and pressurized by a hot roll, whereby a prepreg 3 was obtained. The properties of the prepreg 3 are shown in Table 2.

(Example 4) A prepreg 4 was obtained in the same manner as in Example 3 except that the thermoplastic resin composition 3 was used. The properties of the prepreg 4 are shown in Table 2.

(Example 5) A prepreg 5 was obtained in the same manner as in Example 3, except that the thermosetting resin composition 2 and the thermoplastic resin composition 3 were used. The properties of the prepreg 5 are shown in Table 2.

(Example 6) A reinforcing fiber sheet (basic weight: 193 g/m ² ) in which the reinforcing fiber bundles 1 are aligned in one direction and fiber-opened to form a continuous reinforcing fiber group is made to run in one direction, and a thermosetting resin The composition 2 is freeze-pulverized, the obtained particles are dispersed on one side of the reinforcing fiber sheet, and the particles containing the thermosetting resin composition 2 are heated by an IR heater as a precursor of the dispersed phase of the second thermosetting resin to impregnate the reinforcing fiber sheet. near the surface. Furthermore, a film-like resin sheet having a basis weight of 120 g/m ² containing the thermoplastic resin composition 2 as the precursor of the thermoplastic resin layer was arranged on the same surface as the surface on which the above-mentioned particles were dispersed in the reinforcing fiber sheet, so that The IR heater is heated to melt the thermoplastic resin composition 2, so that it adheres to the entire surface of the reinforcing fiber sheet, pressurized with a roll whose surface temperature is kept below the melting point of the thermoplastic resin composition 2, and then impregnates and strengthens The fibrous sheet is cooled to obtain a prepreg intermediate. Using a knife coater, the thermosetting resin composition 1 as the precursor of the thermosetting resin layer was coated on a release paper with a resin basis weight of 100 g/m ² to produce a thermosetting resin film, and then the above-mentioned thermosetting resin film was superposed on the above-mentioned intermediate body On the surface on the opposite side to which the thermoplastic resin composition 1 was impregnated, the intermediate body was impregnated with the thermosetting resin composition 1 while being heated and pressurized by a hot roll, whereby a prepreg 6 was obtained. The properties of the prepreg 6 are shown in Table 2.

(Comparative Example 1) A prepreg 7 was obtained in the same manner as in Example 1, except that a film-like resin sheet having a basis weight of 120 g/m ² containing the thermoplastic resin composition 3 was used as the thermoplastic resin layer precursor . The properties of the prepreg 7 are shown in Table 2.

(Reference Example 1) Thermosetting resin composition 1 was coated on release paper with a resin basis weight of 50 g/m ² using a knife coater to prepare a resin film. This resin film was overlapped on both sides of a reinforcing fiber sheet (basic weight: 193 g/m ² ) containing reinforcing fiber bundles 1 aligned in one direction, and the thermosetting resin composition was impregnated with the reinforcing fibers while being heated and pressurized with a hot roll. bundle, resulting in prepreg 8.

(Reference example 2) A prepreg 9 was obtained in the same manner as in Reference Example 1 except that the thermosetting resin composition 2 was used.

(Example 7) The prepreg 1 produced in Example 1 and the prepreg 8 produced in Reference Example 1 were cut into predetermined sizes, and two pieces of prepreg 1 and six pieces of prepreg 8 were prepared . The fiber direction of the reinforcing fibers was defined as 0°, and the direction orthogonal to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s indicates mirror symmetry). At this time, the two outermost layers on both sides are laminated so that the prepreg 1 may be formed, and both surface layers of the preform may be arranged so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and a jig or spacer was used as required. While maintaining the shape, a pressure of 0.6 MPa was applied by a press, and the fiber-reinforced plastic 1 was obtained by heating at 180° C. for 2 hours. The properties of the fiber-reinforced plastic 1 are shown in Table 3.

(Example 8) The prepreg 2 produced in Example 2 and the prepreg 9 produced in Reference Example 2 were cut into predetermined sizes, and two pieces of prepreg 2 and six pieces of prepreg 9 were prepared . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). At this time, the two outermost layers on both sides are laminated so that the two outermost layers become the prepreg 2, and the both surface layers of the preform are arranged so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, a pressure of 0.6 MPa was applied by a press, and the fiber-reinforced plastic 2 was obtained by heating at 135° C. for 2 hours. The properties of the fiber-reinforced plastic 2 are shown in Table 3.

(Example 9) The prepreg 3 produced in Example 3 and the prepreg 8 produced in Reference Example 1 were cut into predetermined sizes, and two pieces of prepreg 3 and six pieces of prepreg 8 were prepared. . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). At this time, the two outermost layers on both sides are laminated so that the two outermost layers become the prepreg 3, and the both surface layers of the preform are disposed so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, 0.6 MPa was applied by a press and heated at 180° C. for 2 hours to obtain fiber-reinforced plastic 3. The properties of the fiber-reinforced plastic 3 are shown in Table 3.

(Example 10) The prepreg 4 produced in Example 4 and the prepreg 8 produced in Reference Example 1 were cut into predetermined sizes, and two pieces of prepreg 4 and six pieces of prepreg 8 were prepared. . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). At this time, the two outermost layers on both sides are laminated so that the two outermost layers become the prepreg 4, and the both surface layers of the preform are arranged so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, 0.6 MPa was applied by a press and heated at 180° C. for 2 hours to obtain fiber-reinforced plastic 4. The properties of the fiber-reinforced plastic 4 are shown in Table 3.

(Example 11) The prepreg 5 produced in Example 5 and the prepreg 9 produced in Reference Example 2 were cut into predetermined sizes, and two pieces of prepreg 5 and six pieces of prepreg 9 were prepared . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). At this time, the two outermost layers on both sides are stacked so that the two outermost layers become the prepreg 5, and the both surface layers of the preform are arranged so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, 0.6 MPa was applied by a press and heated at 135° C. for 2 hours to obtain fiber-reinforced plastic 5. The properties of the fiber-reinforced plastic 5 are shown in Table 3.

(Example 12) The prepreg 6 produced in Example 6 and the prepreg 8 produced in Reference Example 1 were cut into predetermined sizes, and two pieces of prepreg 6 and six pieces of prepreg 8 were prepared. . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). At this time, the two outermost layers on both sides are laminated so that the two outermost layers become the prepreg 6, and the both surface layers of the preform are arranged so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, 0.6 MPa was applied by a press and heated at 180° C. for 2 hours to obtain fiber-reinforced plastic 6. The properties of the fiber-reinforced plastic 6 are shown in Table 3.

(Comparative Example 2) The prepreg 7 prepared in Comparative Example 1 and the prepreg 9 prepared in Reference Example 2 were cut into predetermined sizes to prepare two sheets of prepreg 7 and six sheets of prepreg 9 . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). At this time, the two outermost layers on both sides are laminated so that the two outermost layers become the prepreg 7, and the both surface layers of the preform are arranged so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, 0.6 MPa was applied by a press and heated at 135° C. for 2 hours to obtain fiber-reinforced plastic 7. The properties of the fiber-reinforced plastic 7 are shown in Table 3.

(Example 13) A reinforcing fiber sheet (basic weight: 193 g/m ² ) in which the reinforcing fiber bundles 1 were aligned in one direction and fiber-opened to form a continuous reinforcing fiber group was made to run in one direction, and a reinforcing fiber sheet containing as A film-like resin sheet with a basis weight of 120 g/m ² of the thermoplastic resin composition 2 as the precursor of the thermoplastic resin layer is arranged on the surface of the reinforcing fiber sheet, and heated with an IR heater to melt the thermoplastic resin composition 2 and make the thermoplastic resin composition 2 melt. It is adhered to the entire surface of one side of the reinforcing fiber sheet, pressurized with a nip roll whose surface temperature is kept below the melting point of the thermoplastic resin composition 2, and the impregnated reinforcing fiber sheet is cooled to obtain a prepreg intermediate. Using a knife coater, the thermosetting resin composition 1 as the precursor of the thermosetting resin layer was coated on a release paper with a resin basis weight of 100 g/m ² to produce a thermosetting resin film, and then the above-mentioned thermosetting resin film was superposed on the above-mentioned intermediate body The surface on the opposite side to which the thermoplastic resin composition 1 was impregnated was heated and pressurized by a hot roller and passed through an ultrasonic generator immediately, whereby the thermoplastic resin layer precursor was dispersed in the reinforcing fiber sheet. At this time, the frequency of the ultrasonic generator was 20 kHz, the amplitude was 100%, and the pressure was 1.0 MPa. In addition, the distance between the horn of the ultrasonic generator and the prepreg intermediate was about 25 mm, and the time for applying the ultrasonic vibration was about 1.0 second. In this way, the thermosetting resin composition 1 is impregnated with the intermediate body while applying shearing force to the intermediate body to form a dispersed phase of the thermosetting resin, thereby obtaining the prepreg 13 . The properties of the prepreg 13 are shown in Table 4.

(Example 14) A prepreg 14 was obtained in the same manner as in Example 13, except that the reinforcing fiber bundle 2-1 was used. The properties of the prepreg 14 are shown in Table 4.

(Example 15) A prepreg 15 was obtained in the same manner as in Example 13, except that the reinforcing fiber bundle 2-2 was used. The properties of the prepreg 15 are shown in Table 4.

(Example 16) A prepreg 16 was obtained in the same manner as in Example 13, except that the reinforcing fiber bundles 2-3 were used. The properties of the prepreg 16 are shown in Table 4.

(Example 17) The prepreg 13 produced in Example 13 and the prepreg 8 produced in Reference Example 1 were cut into predetermined sizes, and two pieces of the prepreg 13 and six pieces of the prepreg 8 were prepared. . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). In this case, the two outermost layers on both sides are laminated so that the two outermost layers become the prepreg 13, and the both surface layers of the preform are arranged so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, 0.6 MPa was applied by a press and heated at 180° C. for 2 hours to obtain fiber-reinforced plastic 13 . The properties of the fiber-reinforced plastic 13 are shown in Table 5.

(Example 18) In Example 17, the fiber-reinforced plastic 14 was obtained in the same manner as in Example 17, except that the prepreg 14 produced in Example 14 was used. The properties of the fiber-reinforced plastic 14 are shown in Table 5.

(Example 19) In Example 17, the fiber-reinforced plastic 15 was obtained in the same manner as in Example 17, except that the prepreg 15 produced in Example 15 was used. The properties of the fiber-reinforced plastic 15 are shown in Table 5.

(Example 20) In Example 17, the fiber-reinforced plastic 16 was obtained in the same manner as in Example 17, except that the prepreg 16 produced in Example 16 was used. The properties of the fiber-reinforced plastic 16 are shown in Table 5.

(Example 21) A reinforcing fiber sheet (basic weight: 193 g/m ² ) in which the reinforcing fiber bundles 1 are aligned in one direction and fiber-opened to form a continuous reinforcing fiber group, is made to run in one direction, and contains a thermoplastic A film-like resin sheet with a basis weight of 120 g/m ² of the thermoplastic resin composition 3 as the precursor of the resin layer was placed on the surface of the reinforcing fiber sheet, and heated with an IR heater to melt the thermoplastic resin composition 3 and make it After adhering to the entire surface of one side of the reinforcing fiber sheet, pressing the surface temperature with a nip roll whose surface temperature is kept below the melting point of the thermoplastic resin composition 3, and cooling the impregnated reinforcing fiber sheet to obtain a prepreg intermediate. Using a knife coater, the thermosetting resin composition 1 as the precursor of the thermosetting resin layer was coated on a release paper with a resin basis weight of 100 g/m ² to produce a thermosetting resin film, and then the above-mentioned thermosetting resin film was superposed on the above-mentioned intermediate body The surface on the opposite side to which the thermoplastic resin composition 3 was impregnated was heated and pressurized by a hot roller and passed through an ultrasonic generator immediately, whereby the thermosetting resin composition 1 was subjected to shearing force to the intermediate body. The intermediate is impregnated to form a dispersed phase of the thermosetting resin, and the prepreg 21 is obtained. At this time, the frequency of the ultrasonic generator was 20 kHz, the amplitude was 100%, and the pressure was 1.0 MPa. In addition, the distance between the horn of the ultrasonic generator and the prepreg intermediate was about 25 mm, and the time for applying the ultrasonic vibration was about 0.7 seconds. The properties of the prepreg 21 are shown in Table 4.

(Example 22) A reinforcing fiber sheet (basic weight 193 g/m ² ) in which the reinforcing fiber bundles 1 were aligned in one direction and fiber-opened to form a continuous reinforcing fiber group was made to run in one direction, and a reinforcing fiber sheet containing as A film-like resin sheet with a basis weight of 120 g/m ² of the thermoplastic resin composition 4 as the precursor of the thermoplastic resin layer was placed on the surface of the reinforcing fiber sheet, and heated with an IR heater to melt the thermoplastic resin composition 4 to make the thermoplastic resin composition 4 melt. It is adhered to the entire surface of one side of the reinforcing fiber sheet, pressurized with a nip roll whose surface temperature is kept below the melting point of the thermoplastic resin composition 4, and then the one impregnated with the reinforcing fiber sheet is cooled to obtain a prepreg intermediate. Using a knife coater, the thermosetting resin composition 1 as the precursor of the thermosetting resin layer was coated on a release paper with a resin basis weight of 100 g/m ² to produce a thermosetting resin film, and then the above-mentioned thermosetting resin film was superposed on the above-mentioned intermediate body The surface on the opposite side to which the thermoplastic resin composition 4 was impregnated was heated and pressurized by a hot roller and passed through an ultrasonic generator immediately, and the intermediate body was impregnated with the thermosetting resin composition 1 while applying shearing force to the intermediate body. body to form a dispersed phase of thermosetting resin to obtain prepreg 22 . At this time, the frequency of the ultrasonic generator was 20 kHz, the amplitude was 100%, and the pressure was 1.0 MPa. In addition, the distance between the horn of the ultrasonic generator and the prepreg intermediate was about 25 mm, and the time for applying the ultrasonic vibration was about 0.8 seconds. The properties of the prepreg 22 are shown in Table 4.

(Example 23) The prepreg 21 produced in Example 21 and the prepreg 8 produced in Reference Example 1 were cut into predetermined sizes, and two pieces of prepreg 21 and six pieces of prepreg 8 were prepared. . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). At this time, the two outermost layers on both sides are laminated so that the two outermost layers become the prepreg 21, and the both surface layers of the preform are arranged so that the two surface layers of the preform become thermoplastic resin layers containing a thermoplastic resin. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, 0.6 MPa was applied by a press and heated at 180° C. for 2 hours to obtain fiber-reinforced plastic 23. The properties of the fiber-reinforced plastic 23 are shown in Table 5.

(Example 24) The prepreg 22 produced in Example 22 and the prepreg 8 produced in Reference Example 1 were cut into predetermined sizes, and two pieces of the prepreg 22 and six pieces of the prepreg 8 were prepared. . The fiber direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the fiber direction was defined as 90°, and the preforms were laminated by [0°/90°] _2S (symbol s represents mirror symmetry). At this time, the two outermost layers on both sides are stacked so that the two outermost layers become the prepreg 22, and the both surface layers of the preform are disposed so that the thermoplastic resin layers containing the thermoplastic resin may be formed. The preform was placed in a press-forming mold, and jigs and spacers were used as required. While maintaining the shape, 0.6 MPa was applied by a press and heated at 180° C. for 2 hours to obtain fiber-reinforced plastic 24 . The properties of the fiber-reinforced plastic 24 are shown in Table 5.

＜Discussion＞

Comparison of Examples 1 to 6 and Comparative Example 1 shows that the dispersion phase of the second thermosetting resin contained in the thermoplastic resin layer and the reinforcing fibers contained in the thermoplastic resin layer are formed. From the comparison of Examples 1 to 2 and Examples 3 to 6, it is shown that by imparting a dispersed phase of the second thermosetting resin to the reinforcing fiber sheet in which the reinforcing fiber group is formed in advance, it is possible to control the amount of the thermoplastic resin layer contained in the thermoplastic resin layer. The size of the dispersed phase of the second thermosetting resin that reinforces the fiber bond.

According to the comparison between Examples 7 to 12 and Comparative Example 2, it is shown that an integrally molded product is formed by welding by having the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer and the reinforcing fibers contained in the thermoplastic resin layer. At this time, the thermoplastic resin layer can be suppressed from flowing out, and a molded product with high bonding quality can be produced. Furthermore, according to the comparison of Example 7 with Example 12 and the comparison of Example 10 with Example 11, it is shown that the second thermosetting resin contained in the thermoplastic resin layer has a high glass transition temperature because of the high glass transition temperature during welding. The amount of deformation due to heat at the time of forming an integrally molded product is reduced, the flow of the thermoplastic resin layer can be suppressed, and a molded product with high bonding quality can be produced. A comparison between Example 1 and Example 13 shows that the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer is densely formed by vibrating the bonding surface of the thermoplastic resin layer and the thermosetting resin layer. In addition, according to the comparison of Examples 13 to 16, it was shown that the use of reinforcing fibers with high surface free energy promotes the fluidity of the resin and the volume of the dispersed phase of the second thermosetting resin relative to the thermoplastic resin contained in the thermoplastic resin layer. The ratio becomes larger. From the comparison of Examples 21 to 22 and Comparative Example 1, it was confirmed that the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer can be formed by vibrating the bonding surface of the thermoplastic resin layer and the thermosetting resin layer. In any one of Examples 17 to 20 and Examples 23 to 24, it is shown that the dispersion phase of the second thermosetting resin contained in the thermoplastic resin layer and the reinforcing fibers contained in the thermoplastic resin layer are formed by welding. In the case of an integrally molded product, the thermoplastic resin layer can be suppressed from flowing out, and a molded product with high bonding quality can be produced.

Table 1 Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition Thermosetting resin (epoxy resin) Tetraglycidite® ("Araldite®" MY721) 50 Bisphenol A epoxy resin ("jER®"825) 50 50 Phenol Novolak Epoxy Resin ("jER®"154") 50 Amine compounds 4,4'-Diaminodiphenylene (SEIKACURE-S) 45.1 Dicyandiamide (DICY7) 6.8 Viscosity modifier Polyether dust ("Sumikaexcel®" PES5003P) 7 7 hardening condition Hardening temperature(℃) 180 135 Hardening time (hours) 2 2 Thermosetting Resin Cured Properties Glass transition temperature (℃) 195 137

Table 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Reference Example 1 Reference example 2 Reinforcing fiber bundles type Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Surface Free Energy (mJ/m ² ) 15 15 15 15 15 15 15 15 15 Thermosetting resin layer Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 2 thermoplastic resin layer Thermoplastic resin composition 2 Thermoplastic resin composition 1 Thermoplastic resin composition 2 Thermoplastic resin composition 3 Thermoplastic resin composition 3 Thermoplastic resin composition 2 Thermoplastic resin composition 3 - - Polyamide 6 low melting point polyamide Polyamide 6 PPS PPS Polyamide 6 PPS Whether vibration is applied by an ultrasonic generating device none none none none none none none none none Composition of thermoplastic resin layer Second Thermoset Resin Region Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 2 - - - Size of the second thermosetting resin region (μm) 2 3 20 20 30 30 - - - Whether the plurality of reinforcing fibers are bonded to the second thermosetting resin Have Have Have Have Have Have none none none Volume ratio A (volume %) of the dispersed phase of the second thermosetting resin to the thermoplastic resin contained in the thermoplastic resin layer 11 19 15 13 10 12 0 - - Volume ratio B (volume %) of the dispersed phase of the second thermosetting resin relative to the carbon fibers contained in the thermoplastic resin layer 4 7 32 26 28 30 0 - - The sum of the volume ratio (volume %) of the reinforcing fibers contained in the thermoplastic resin layer to the second thermosetting resin 26 32 42 38 34 33 18 - -

table 3 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Comparative Example 2 Reinforcing fiber bundles type Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Surface Free Energy (mJ/m ² ) 15 15 15 15 15 15 15 Thermosetting resin layer Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 1 Thermosetting resin composition 2 thermoplastic resin layer Thermoplastic resin composition 2 Thermoplastic resin composition 1 Thermoplastic resin composition 2 Thermoplastic resin composition 3 Thermoplastic resin composition 3 Thermoplastic resin composition 2 Thermoplastic resin composition 3 Polyamide 6 low melting point polyamide Polyamide 6 PPS PPS Polyamide 6 PPS Whether vibration is applied by an ultrasonic generating device none none none none none none none Preform forming conditions Hardening temperature(℃) 180 135 180 180 135 180 135 Hardening time (hours) 2 2 2 2 2 2 2 Composition of thermoplastic resin layer Second Thermoset Resin Region Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 2 - Size of the second thermosetting resin region (μm) 3 5 20 20 30 30 - Whether the plurality of reinforcing fibers are bonded to the second thermosetting resin Have Have Have Have Have Have none Volume ratio (volume %) of the dispersed phase of the second thermosetting resin to the thermoplastic resin contained in the thermoplastic resin layer 12 twenty one 17 13 10 13 0 Volume ratio (volume %) of the dispersed phase of the second thermosetting resin to the carbon fibers contained in the thermoplastic resin layer 6 8 34 27 28 30 0 The sum of the volume ratio (volume %) of the reinforcing fibers contained in the thermoplastic resin layer to the second thermosetting resin 28 35 44 39 34 36 18 Weldability Evaluation of Fiber Reinforced Plastics A A A A B B C Adhesive layer thickness of integrally molded product (μm) twenty four 28 48 50 30 11 5

Table 4 Example 13 Example 14 Example 15 Example 16 Example 21 Example 22 Reinforcing fiber bundles type Reinforcing fiber bundle 1 Reinforcing fiber bundle 2-1 Reinforcing fiber bundles 2-2 Reinforcing fiber bundles 2-3 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Surface Free Energy (mJ/m ² ) 15 9 20 32 15 15 Thermosetting resin layer Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 thermoplastic resin layer Thermoplastic resin composition 2 Thermoplastic resin composition 2 Thermoplastic resin composition 2 Thermoplastic resin composition 2 Thermoplastic resin composition 3 Thermoplastic resin composition 4 Polyamide 6 Polyamide 6 Polyamide 6 Polyamide 6 PPS PEKK Whether vibration is applied by an ultrasonic generating device Have Have Have Have Have Have Composition of thermoplastic resin layer Second Thermoset Resin Region Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Size of the second thermosetting resin region (μm) 1 1 1 1 1 1 Whether the plurality of reinforcing fibers are bonded to the second thermosetting resin Have Have Have Have Have Have Volume ratio A (volume %) of the dispersed phase of the second thermosetting resin to the thermoplastic resin contained in the thermoplastic resin layer 12 8 20 25 12 10 Volume ratio B (volume %) of the dispersed phase of the second thermosetting resin to the reinforcing fibers contained in the thermoplastic resin layer 5 3 10 13 5 6 The sum of the volume ratio (volume %) of the reinforcing fibers contained in the thermoplastic resin layer to the second thermosetting resin 28 17 38 45 27 29

table 5 Example 7 Example 17 Example 18 Example 19 Example 20 Example 23 Example 24 Reinforcing fiber bundles type Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Reinforcing fiber bundle 2-1 Reinforcing fiber bundles 2-2 Reinforcing fiber bundles 2-3 Reinforcing fiber bundle 1 Reinforcing fiber bundle 1 Surface Free Energy (mJ/m ² ) 15 15 9 20 32 15 15 Thermosetting resin layer Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 1 thermoplastic resin layer Thermoplastic resin composition 2 Thermoplastic resin composition 2 Thermoplastic resin composition 2 Thermoplastic resin composition 2 Thermoplastic resin composition 2 Thermoplastic resin composition 3 Thermoplastic resin composition 4 Polyamide 6 Polyamide 6 Polyamide 6 Polyamide 6 Polyamide 6 PPS PEKK Whether vibration is applied by an ultrasonic generating device none Have Have Have Have Have Have Preform forming conditions Hardening temperature(℃) 180 180 180 180 180 180 180 Hardening time (hours) 2 2 2 2 2 2 2 Composition of thermoplastic resin layer Second Thermoset Resin Region Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 1 Thermosetting resin composition 1 Thermosetting resin composition 2 Thermosetting resin composition 1 Thermosetting resin composition 1 Size of the second thermosetting resin region (μm) 3 2 2 2 2 2 2 Whether the plurality of reinforcing fibers are bonded to the second thermosetting resin Have Have Have Have Have Have Have Volume ratio A (volume %) of the dispersed phase of the second thermosetting resin to the thermoplastic resin contained in the thermoplastic resin layer 12 13 9 twenty two 26 13 12 Volume ratio B (volume %) of the dispersed phase of the second thermosetting resin to the reinforcing fibers contained in the thermoplastic resin layer 6 6 5 12 15 6 8 The sum of the volume ratio (volume %) of the reinforcing fibers contained in the thermoplastic resin layer to the second thermosetting resin 28 30 20 39 47 29 30 Weldability Evaluation of Fiber Reinforced Plastics A A B A A A A Adhesive layer thickness of integrally molded product (μm) twenty four 25 25 27 25 27 25

Although the present invention has been described in detail or with reference to specific embodiments, it should be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on the Japanese Patent Application (Japanese Patent Application No. 2020-096947) for which it applied on June 3, 2020, The content is used here as a reference.

1,14: Reinforcing fibers 2: Thermosetting resin layer 3: Thermoplastic resin layer 4: Dispersed phase of the second thermosetting resin 5: Fiber reinforced plastic or prepreg 6: Fiber direction 8: Sectional observation surface 9: Observe the image 10: Interface 12: Reinforcing fiber group 100: End 120: vertical line 130: Profile Curve

FIG. 1 is a schematic diagram showing an embodiment of the prepreg or fiber-reinforced plastic of the present invention. 2 is a view illustrating a cross-sectional view of a prepreg or fiber-reinforced plastic according to an embodiment of the present invention. 3 is a schematic diagram of a cross section perpendicular to the plane of the prepreg or the plane of the fiber-reinforced plastic according to the present invention, which is used to assist in explaining the method for obtaining the average boundary line of the interface between the thermosetting resin layer and the thermoplastic resin layer.

1,14: Reinforcing fibers

2: Thermosetting resin layer

3: Thermoplastic resin layer

4: Dispersed phase of the second thermosetting resin

5: Fiber reinforced plastic or prepreg

12: Reinforcing fiber group

Claims (17)

A fiber-reinforced plastic comprising: a reinforcing fiber group containing reinforcing fibers, a thermosetting resin layer containing a first thermosetting resin, and a thermoplastic resin layer, wherein, having the thermoplastic resin layer as the surface layer of the fiber-reinforced plastic, The interface between the thermoplastic resin layer and the thermosetting resin layer is located inside the reinforcing fiber group, The thermoplastic resin layer includes a dispersed phase of the second thermosetting resin. The fiber-reinforced plastic of claim 1, wherein the reinforced fiber contained in the thermoplastic resin layer is in contact with the dispersed phase of the second thermosetting resin. The fiber-reinforced plastic of claim 1 or 2, wherein the reinforcing fibers contained in a plurality of the thermoplastic resin layers are bonded by the second thermosetting resin. The fiber-reinforced plastic according to any one of claims 1 to 3, wherein the long axis length of the dispersed phase of the second thermosetting resin is 50 nm or more. The fiber-reinforced plastic of claim 4, wherein the length of the long axis of the dispersed phase of the second thermosetting resin is 1 μm or more. The fiber-reinforced plastic according to any one of claims 1 to 5, wherein, in a cross section in the thickness direction, the volume ratio of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer is relative to the volume of the dispersed phase in the reinforcing fiber group The thermoplastic resin layer is 10% by volume or more with respect to 100% by volume. The fiber-reinforced plastic according to any one of claims 1 to 5, wherein, in a cross-section in the thickness direction, the volume ratio of the dispersed phase of the second thermosetting resin contained in the thermoplastic resin layer is relative to that in the thermoplastic resin layer. The amount of the reinforcing fibers contained is 3% by volume or more and 50% by volume or less with respect to 100% by volume. The fiber-reinforced plastic according to any one of claims 1 to 5, wherein the sum of the volume ratios of the reinforcing fibers and the second thermosetting resin contained in the thermoplastic resin layer is relative to the thickness of the cross section from the thermoplastic resin The interface between the layer and the thermosetting resin layer is 10 vol % or more for 100 vol % of the region of 50 μm from the surface of the thermoplastic resin layer. The fiber-reinforced plastic according to any one of claims 1 to 8, wherein the second thermosetting resin and the first thermosetting resin are the same type of resin. The fiber-reinforced plastic according to any one of claims 1 to 9, wherein the glass transition temperature of the second thermosetting resin is 150° C. or higher. An integrally formed product, wherein a first member and a second member are joined through the thermoplastic resin layer of the fiber-reinforced plastic, and the first member comprises the fiber-reinforced plastic according to any one of claims 1 to 10. The integrally molded product of claim 11, wherein in the integrally molded product, the distance t between the thermosetting resin layer and the second member is 10 μm or more. A prepreg comprising: a reinforcing fiber group containing reinforcing fibers, a thermosetting resin layer containing a first thermosetting resin, and a thermoplastic resin layer, wherein, having the thermoplastic resin layer as the surface layer of the prepreg, The interface between the thermoplastic resin layer and the thermosetting resin layer is located inside the reinforcing fiber group, The thermoplastic resin layer includes a dispersed phase of a second thermosetting resin in contact with the reinforcing fibers. The prepreg of claim 13, wherein the length of the major axis of the dispersed phase of the second thermosetting resin is 1 μm or more. The prepreg according to claim 13 or 14, wherein the sum of the volume ratios of the reinforcing fibers and the second thermosetting resin contained in the thermoplastic resin layer is relative to the thickness of the cross section from the thermoplastic resin layer and the thermosetting resin. The interface of the resin layer is 10 vol % or more of 100 vol % of the region of 50 μm on the surface of the thermoplastic resin layer. The prepreg of any one of claims 13 to 15, wherein the second thermosetting resin and the first thermosetting resin are the same kind of resin. A fiber-reinforced plastic as claimed in any one of claims 1 to 10, a monolithic product as claimed in claim 11 or 12, or a prepreg as claimed in any one of claims 13 to 16, wherein a Wilhelmy The reinforced fiber whose surface free energy measured by the ) method is 10-50 mJ/m ² is used as the reinforced fiber.

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